Paving-block composition.



No Drawing.

UNITED STATES PATENT ornron.

AUGUST nnrnnsunmnn, or NEUSTADT-ON-THIEhHARDT, GERMANY.

PAVING-BLOCK COMPOSITION.

Specification of Letters Patent.

Patented May 27, 1013.

Application filed March 17, 1911. Serial No. 615,103.

paving-blocks and consists of com'minuted naturalor artificial stonymaterial, preferably such as basalt, granite, porphyry, lava, syenite,quartz, glass, slag, etc., in admixture with clay.-

In accordance with the invention, the

stony material is comminuted and the grains of different size separatedfrom each other by sifting so that a number of differentlysized stonematerials are obtained, for instance one sort containing grains of 16mm. in diameter; a further sort whichis fine enough to pass through themeshes of a sieve having 80 meshes in each square centimeter, which ishowever retained by a 100.

mesh sieve; a third sort having grains finer than the meshes of a 100mesh sieve and blgger than the meshes of a 300 mesh sieve;

and finally a fourth sort containing grains finer than the meshes of a300 mesh sieve. Besides the different sorts of granular ma terial amineral dust is prepared, preferably by mixing granular stone materialwith a; to I, of its weight of fire-proof clay and grinding such mixtureto a high degree of fineness, so that preferably '20 to 30% of the dustis fine enough to pass through the meshes of a 5,000 mesh sieve; Theclay and stone-dust of this mixture react during the burning to yield asilicate bond, without shrinkage of the mass or formation of a porousproduct. These differently-sized sorts of raw material are mixed witheach other in definite proportions, for instance so that, for each 100parts in weightof the final mixture, 25 to 50 parts of the coarsestmaterial, 15 to 20 parts of the three finer sorts of granular materialand 20 to 30 parts of the fine stone-cla dust are taken. The mixture isthen molstened within a receptacle with stirring device so that it canbe molded into blocks either with a, wetmold or with a hydraulic drymold. The molded blocks are dried if necessary and thereafter burned insuitable kilnsv till the mass be:

comes clinkered. The burned blocks are subjected to a slow coolingprocess in order to avoid their becoming brittle. The size of the blocksis preferably so chosen that their surface'which is designed for use hasedges -of about 24 centimeters and 30 centimeters lengths, whereas thethickness of the blocks is about 612 centimeters.

By mixing different sorts of ston material it is possible to obtainpavinglocks of special properties; undesired properties resultingfromspecial raw material which may be at disposal may be overcome byaddin to such raw material stony material of different quality.

The paving-blocks manufactured as above described are embedded in mortarand the interstices which preferably are made very tight are filled withthin cement mortar or with asphalt. The pavement thus produced has greatdurability, does not become slippery and is not liable to the formationof dust and to the penetration of water.

If desired the paving-blocks may, before they are introduced into thekiln and whlle their surfaces still retain a certain degree of moisture,beprovided with a layer of quartzsand. This may be done either bydipping the blocks into sand, if the blocks are formed ,with a wet mold,or by directing a sand blast jet against the blocks if formed with a dryhydraulic mold. If-the blocks prepared in thisway are burned, theyobtain an homogeneously colored rough surface, whereas the blocksmanufactured without such infusible sand coating are provided with athin glazing coating, which however disappears in very short time whenthe blocks are in use.

What I claim is:

A composition for clinkered paving-blocks consisting essentially of amixture of per cent. and upward of a plurality of sorts ofdifferently-sized gran'ular refractory stony materials, in conjunctionwith a void-filling and binding mixture of a fiuxing dust derived fromsuch stony materials, and fireclay.

In testimon whereof, I afiix my signature Witnesses HEINRICH THRIP,RunoLF ZUNGFLEISCH:

Copies of this patent may be obtained for fl ve cents each, byaddressing the Commissioner of latents,

